Recent studies suggest inflammatory bowel disease, especially Crohn's disease, is caused by cell wall defective variants of group Va Pseudomonas-like bacteria or Mycobacteria. This work is provocative, but unconfirmed. The purpose of the present study is to culture tissue from patients with inflammatory bowel disease using optimal techniques to recover L-forms of the previously implicated organisms as well as other bacteria. This includes the use of multiple agar and broth media for primary isolation, and the use of scanning electron microscopy for detecting the L-form state. Specimens will be obtained from an ongoing study of inflammatory bowel disease in which the present participants are examining for animal transmissibility and viral agents. Serologic tests and cultures will also be performed in animals challenged with bowel tissue to support or refute the possibility that L-forms account for transmissibility. Finally, animals will be challenged with L-forms in an attempt to reproduce the pathologic findings of inflammatory bowel disease.